1. Field of the Invention
The present invention generally relates to a control device for a direct fuel injection spark ignition engine. More specifically, the present invention relates to a control device that is suitable during cold starting and the other times, or when it is necessary to warm up a catalyst for exhaust purification provided to the exhaust channel.
2. Background Information
One example of a direct fuel injection spark ignition engine with a fuel injection control is disclosed in Japanese Patent No. 3325230. This patent discloses a fuel injection control that is applied when the catalytic converter is in an un-warmed state, i.e., when the temperature of the catalyst is lower than its activation temperature. In this fuel injection control, the fuel injection is divided into at least two injection composed of an early-stage injection and a later-stage injection. Thus, an air-fuel mixture with a partially variable air-fuel ratio is formed in an interval that extends from the intake stroke to ignition timing. In the early-stage injection, fuel is injected prior to the later-stage injection such that an air-fuel mixture with an air-fuel ratio that is leaner than the theoretical air fuel ratio is generated to allow combustion to be extended using the fuel of the later-stage injection. The ignition timing is retarded by a predetermined amount from MBT. The ignition timing in the no-load region of the engine is set to occur prior to the compression top dead center; and ignition timing in the low-speed, low-load region, excluding the no-load region, of the engine is retarded until the compression top dead center or later.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved control apparatus for a direct-injection spark-ignition internal combustion engine. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.